Fuel injectors for two-stroke engine, and particularly one that can be used for a cylinder head fuel injection system allow a two-stroke engine to be so improved as to rival the four-stroke engine. As a result, the injection system and the structure of an injector for two-stroke engines have been major subjects for a number of engine research institutes. Leading auto-makers such as Japan's TOYOTA, SUBARU, MAZDA, and NIPPON DENSO, General Motors (GM) and FORD in the U.S., and ORBITAL Engine Co. of Australia have been engaged in relevant research. The most significant jet-type fuel injector is shown in FIG. 1 and is one developed by the Australian ORBITAL Engine Co. The main body of this injector has a fuel passage 100 and the main valve has an air passage 200. When the main valve is opened, a predetermined amount of fuel from the fuel passage can be atomized and injected by means of high-pressure air.
However, such a jet-type fuel injector for a two-stroke engine has the following problems:
(1) the atomizing effect is limited, because only the air from the main valve will enter into the oil passage of the main body of injector to push out the fuel therein; and PA1 (2) because not only is the pressure provided from a stream of air insufficient but, also, fuel in the fuel passage is not pre-mixed with air.